[Systemic treatment of breast cancer: professional guideline]

Over the years since the 4th Breast Cancer Consensus Conference, a substantial body of new evidence based on clinical trial results has been published, necessitating an update of the 2020 recommendations. This professional guideline primarily reflects the current ESMO, NCCN, ABC, and St. Gallen Consensus Conference statements and recommendations. From a didactic perspective, the text first addresses early-stage breast cancer, followed by locally advanced, locoregionally recurrent, and metastatic breast cancer. At the beginning of both the early-stage and metastatic breast cancer sections, we provide a summary of general principles relevant to the respective field, which apply to the subsequent subsections. Within these subsections, therapeutic options are discussed according to genomic subgroups. At the end of the recommendations, considerations for the management of certain rare clinical scenarios are summarized. The appendices cover, among other topics, multidisciplinary team (tumor board) requirements, recommended chemotherapy protocols, and the definition of menopause.